Multifont selection

ABSTRACT

A high speed printer employing an automatic font selection activated by coded indicia on a continuous loop-printing belt cooperating with a plurality of sensors coupled in turn to a counter and decoder system for automatically detecting the particular font speed necessary for controlling the hammer action of the printer.

Unlted States Patent 11 1 1111 3,845,709

Gardiner 145] Nov. 5, 1974 MULTIFONT SELECTION 1605.610 9/1971 McDowellet 111. 101/111 [75] Inventor: Derek J Gardiner Sudbury Mass 1605,1113 91971 DePuy et al. 101/111 [73] Assignec: lomec Corporation, Southboro,Primary Examine1-Robcrt E. Pulfrey Muss. Assistant ExaminerEdward M.Coven [22] Filed: Feb. 26, 1973 Attorney, Agent, or FirmDaniel M. Rosen1211 Appl. No.1 335,862 1571 ABSTRACT 1 A high speed printer employingan automatic font se- 152] U.S.'Cl.. 101/93 C, 101/111 lection activatedy coded ind n a ont nu s [51] 1111. C1 B41j 5/10 p-p g belt p t g with ap u y o $911- [58] Field of Search 101/93 C, 111 sors o p i turn to aounte and de oder system for automatically detecting the particular fontspeed [56] References Cited necessary for controlling the hammer actionof the UNITED STATES PATENTS P1111161- 3,115,092 12/1963 Sasaki 101 111x 1 Claim, 1 Drawing Figure ABC ABC ABC U ""ll l] 11 11 *---*11 9 2/ 2/,

1/ w M p R 12 1 014m 8 comp/mural? V gay 3 2g 111 5: 1

P/mvr 16 HAMMER MULTIFONT SELECTION This invention relates to high speedprinters and, more particularly, to automatic multifont selectionemployable with such high speed printers.

High speed printers such as the type to be described herein typicallyemploy an endless type carrier coacting with a plurality of a number ofsets of hammers, one hammer for each character position along a line anda hammer driver for each set of hammers which is timeshared among thehammers of a set.

lmpact line printers typically may be characterized by moving endlessprint carriers having a number of characters etched, engraved, embossedor otherwise formed on or attached to the carrier surface coacting witha print hammer at each character position on a line so as to effectprinting on a print medium such as paper or the like. Storage, controland timing circuitry are utilized to accurately actuate a particularhammer at the precise time a character desired is to be printed and acharacter is in registration with that position.

Ahigh speed printer operable in accordance with the foregoing generaldescription is described with greater particularity in-U.S. Pat. No.3,795,186, by Robert H. Curtis et al and assigned to the predecessor ininterest of the assignee of the present invention. As is described inthe aforementioned copending application, hammer firing must beprecisely timed to impact characters at their proper position in orderto prevent ghosting, smud gin g, misregistration of printed charactersand the like. Thus, the hammer drive circuits must deliver extremelyaccurate actuation pulses precise in rise time, duration and magnitude.Furthermore, such pulses must be most accurately timed to actuate thehammer precisely as printing is required. lt is conventional inprinters, however, to employ various types of fonts for printing.Obviously, where character sizes and sets change from type belt to. typebelt, a variation in the timing of the control circuitry actuating theprint hammers must be effected in order to more precisely select thetiming necessary to correspond to a particular font belt.

Prior art devices have employed variations in font timing by means of anexternally actuatable switch which must be moved from one position toanother in accordance with the variation of the font set. Other methodshave employed replacement of timing circuits by means of manualreinsertion of printed circuit cards and the like corresponding to aparticular type'font belt selected.

It is, therefore, the object of the presentinvention to provide anarrangement for use in a high speed line printer which will permit theautomatic selection of timing and triggering to occur in response tochanging the font belt.

It is a further object of the present invention to enable a singleprinter to automatically undergo variation in circuit timing inaccordance with a predeter'mined coded system located on the font beltitself.

It is still a further object of the present invention to provide asimple and economical'method of varying the internal-timing of a hammerdrive for purposes of selecting character sets varying in size inaccordance with pluralities of predetermined fonts, the control for theselection being located directly upon the font belt.

The foregoing objects are effected by locating a first and second set ofindicia on the font belt coded in aca 2 cordance with the size of theparticular font set located on that belt. A sensor mechanismis adaptedto transduce the plurality of indicia to provide a coded signal. Adecoding circuit is responsive to the coded signal for selecting one ofa plurality of font speed timing circuits which, in turn, control thetiming to the hammer drive circuits. I

The foregoing objects and brief description of'the present inventionwill become more apparent from the following more detailed descriptionof the present invention and appended drawing wherein the FIGUREillustrates a logic diagramshowingthe interrelationship of thecomponents of the present invention with a dual indicia belt.

Referring to FIG. 1, a font belt 101is illustrated having a font set 12located thereon. Directly beneath the font set on the font belt is afirst plurality of primary indicia l4 and a second plurality ofsecondary indicia l6. Relationship between the indicia l4 and theindicia 16 are indicative of the nature of the character font providedin the area 12. Thus, as shown in the FIGURE, the font belt 10 includesa group of secondary indicia 14 for every primary indicia 16. Theprimary/secondaryrelative position is, therefore, a coded representationof the particular font size contained within the segment l2.

Should the font size of the segment 12 differ from belt to belt, forexample, the relative position of the primary/secondary indicia willvary accordingly.'The type belt 10 may be formed of a single loop ofsteel having a homogeneous characteristic with raised letters andindicia, formed in a well known manner andas illustrated in greaterdetail in co-pending application, Ser. No. 857,507 filed Sept. 12, 1969by Richard Holzman, et al and assigned to the predecessor in interest ofthe assignee of the present invention.

Cooperating with the steel belt for sensing the primary and secondaryindicia are sensors Band 20. The sensors 18 and 20, which may bemagnetic in nature, operate to sense the raised area corresponding tothe indicia 16 and 14 for providing anappr opriate signal therefrom. Asuitable form of sensor which may be utilized in conjunction with thepresent invention is illustrated in copending application, Ser. No.857,506 filed Sept. 12, I969 by Robert H. Curtiss and assigned to thepredecessor in interest of the assignee of the present invention.

The output derived from the transducers l8 and 20 are coupled to acounter 22 which is, in turn, coupled to a decoding unit 24. The outputof the transducersl8 and 20 are also coupled to a character generator 26which is in turn coupled to a comparator 28. Data input is applied alongline 30 to a memory 32, and, in turn, supplied to the same comparator283. The output of the comparator 28 is supplied along a line 34'toadrive control circuit 36. The drive control circuit receives outputsfrom one of a plurality of selected font timing circuits indicated as38, 40, and 42 respectively. Obviously, further font selection timingcircuits may be em- 3 ploying 6 sets of 64 characters, a primary indiciawould appear six times, once for every 64 secondary indicia; in a beltemploying 24 sets of 16 characters, a primary indicia would appear 24times, once for every 16 characters, etc. The requisites of timing andcontrol are fully set forth in US. Pat. No. 3,795,l86 for 6 sets of 64character belt. The requisites for a timing circuitry for effecting thenecessary print cycles to accomplish an operation employing a-characterbelt of 6 sets of 64 characters is also clearly set forth in saidapplication Ser. No. 876,770, the disclosure of which is specificallyincorporated herein by reference. The present invention provides forchanging of this timing in accordance with the variation of thecharacter sets employed on a variation of font belt. Thus, the timingprovided from circuits 38, 40, and 42 are each coupled by means ofsuitable coupling to the comparator unit 28 and the drive control 36 inthe same manner as illustrated in the said US. Pat. No. 3,795,186 forsetting the drive control circuit 36, which, in turn, controls thehammer drive circuit 44 and drives the print hammers 46. A fulldescription of driver control, hammer driver, and printer hammercircuits may also be found in US. Pat. No. 3,795,l86.

The operation of the present invention will now be described in greaterdetail. Upon removal and replacement of a type belt 10, the machine isactivated. Upon activation of the machine, the sensors 18 and 20 operateto transduce pulses in accordance with the relative position of theprimary and secondary indicia l6 and 14 respectively. The counter unit22 responds to an activation signal from the transducer 20 which willset the counter and allow it to continue to count pulses from transducer20 at a predetermined rate until the transducer 18 picks up a primaryindicia signal and resets the counter. Thus, the counter will count to apredetermined total level corresponding to the relative position betweenthe two sets of indicia. The decoder circuit 24 will respond to thispredetermined total level for providing a one out of n-outputalong theplurality of out- 'put lines indicated beneath the element 24 to one ofthe appropriate timing circuits in accordance with the relativepositioning of the primary and secondary indicia. Once having selectedan appropriate timing circuit, the print hammer timing cycle may bearranged to more precisely and accurately place the printed characterson the paper. It should be noted in connection with the drawing that theprint hammer unit 46 operates with the type face 12 in conjunction withan intervening sheet of paper such as is more fully described in US.

Pat. No. 3,795,186.

The timing operation may be accomplished by the use of a three bitnumber which will allow sufficient variation for any practical number ofbelts. Since the belts are replacable as a unit, a much more convenientmethod of automatically selecting the particular font timing desired fordriving the hammer in a line printer has thus been disclosed. It is onlynecessary for variation of the font size to change the belt itself, theindicia marks located thereon providing the indication of the variationin speed timing which the circuit need employ in order to select thedesired printing speed.

Thus what has been described above is a multifont capability in atypical line printer such as is described herein.

Other modifications, variations, substitutions and additions may be madeto the foregoing description in accordance with the spirit and scope ofthe invention as will be apparent to one skilled in the art.

What is claimed is:

1. A print timing apparatus for use in font belt printing for printingin accordance with the timing of any of a plurality of fonts having adifferent number of characters per set, each different font carried on afont belt, said font belt including a plurality of primary indicia and aplurality of secondary indicia, said primary indicia corresponding toeach font on said belt and said secondary indicia corresponding to eachcharacter on a font, said first and second indicia positioned on saidbelt relative to each other in accordance with the size characteristicof each said font, said apparatus comprising a plurality of timing meansfor controlling the speed actuation of said printer in accordance withthe size font on said font belt, a first sensor for sensing said primaryindicia, a second sensor for sensing said secondary indicia, a countercoupled to said second sensor and responsive to each secondary indiciafor accumulating a count corresponding to said sensed secondary indicia,said counter having a reset input further coupled to said first sensorand responsive thereto to be reset by each sensed primary indicia, thetotal count thus accumulated in said counter corresponding to a fontsize, decoding means coupled to said counter and responsive to eachtotal level count accumulated in said counter forproviding a uniqueoutput, and means coupling each unique output of said decoder to acorresponding one of said plurality of timing means for selecting one ofsaid timing means of said printer.

1. A print timing apparatus for use in font belt printing for printingin accordance with the timing of any of a plurality of fonts having adifferent number of characters per set, each different font carried on afont belt, said font belt including a plurality of primary indicia and aplurality of secondary indicia, said primary indicia corresponding toeach font on said belt and said secondary indicia corrEsponding to eachcharacter on a font, said first and second indicia positioned on saidbelt relative to each other in accordance with the size characteristicof each said font, said apparatus comprising a plurality of timing meansfor controlling the speed actuation of said printer in accordance withthe size font on said font belt, a first sensor for sensing said primaryindicia, a second sensor for sensing said secondary indicia, a countercoupled to said second sensor and responsive to each secondary indiciafor accumulating a count corresponding to said sensed secondary indicia,said counter having a reset input further coupled to said first sensorand responsive thereto to be reset by each sensed primary indicia, thetotal count thus accumulated in said counter corresponding to a fontsize, decoding means coupled to said counter and responsive to eachtotal level count accumulated in said counter for providing a uniqueoutput, and means coupling each unique output of said decoder to acorresponding one of said plurality of timing means for selecting one ofsaid timing means of said printer.